Help with Berber Skinks set up

Question
I am getting a pair of berber skinks from pet shop. They are 15 months old. Male and female approx 10 inches long used to living in small glass tank with reptiglow 10 on top, heat mat, a cave enclosure and playsand. They eat only meal worms and nothing else except some fruit and veg - male likes to laze in the 'sun' next to the cave where female hides most of the time. Very friendly and like to climb all over people.

I am getting large 3ft x 18" x 18" glass vivarium for them with top and side vents - the lamps will be quite far from the skinks 15-16 inches.  I have been thinking to get 2ft reptiglow 10 and Sun Glow halogen lamp to put in medium Glow Light fitting that is supposed to reflect light after you turn it off. They have not seen daylight bulbs before. Exo terra have 50w-150w lamps. I want warm spot but not very hot that it's not comfortable for them. I don't know how intense the light is that it gives off and if this is the right lamp? What is the right wattage? Is it ok to have only 2ft UV lamp to allow placement of Glow Light next to it. Am I going over the top? They have been ok with UV lamp only for a year or so

I am also thinking to get 2 caves - one completely enclosed and one semi closed so that some light gets through. Where should I put them.

What substrate should I get - I was told to shake calcium on the live food - I have seen calcium sand - could I not just use this as substrate and then not have to buy calcium powder to put on the worms? should I put different types of substrate in various parts of the tank?

Am I ok without a thermometer. Can I just observe them to see that they look comfortable and not behaving strangly. The heating is always on in the room around 20 degrees.

Do you turn the heat mat off at night and in the summer when it gets very hot?

Do you need to worm them or other similar maintenance?

Do they need to eat dead or dry special foods to make sure they have enough nutrients if they only eat meal worms and no other live food?

Answer
 I would get Megaray mercury vapor bulbs from ReptileUV.com.  Bob McCarger is an expert on reptile lighting and if you give him the dimensions of the tank, he will customize the lighting you need.  
 Two caves is a good idea.  Skinks do like multiple hides to feel secure.  If one is warmer than the other it will give them choice.
  Stick with playsand.  Calcisand causes impaction in many reptile species.  I wish they'd take it off the market.  You might also get som sphagnum moss for one end, that you can keep slightly moist.  Both areas should be at least 3 inches deep, skinks like to burrow.  And that means better to the heat mat and go for a CHE.  Warmth should always come from above.
  You should always have a digital thermometer  with a probe.  These can be gotten at any store with a patio section like Walmart or Lowes.
  The CHE (ceramic heat emitter) should be on a rheostat, this will keep the heat constant and shut off automatically if the tank or ambient heat gets above what you set it for.
  After they have been in your home two weeks, they should be seen by a good reptile veterinarian.
  Berber skinks are omnivores. They need a good calcium rich salad with some of the following greens and vegetables: collards, mustard greens, dandelion greens, turnip tops, arugula, mache, winter squashes, sweet potatoes, green beans, snap beans.  And they should have live prey, sized so they can be eaten easily if babies.  They really don't need commercial dry food.